During the period 1790-1874 the coast at Ferring receded some 155 m. This sharp coastal recession was a result of the headlands breaching at Thyborøn, which resulted in a drastic change in currents and sand transport along the coast.
After the first breakwaters were built at Ferring, the coast stabilized and shoreline receding slowed. From 1874 to 1980 the shoreline retreated only 50 m. Today the coast is stable and there is no more retreat.
The first groynes
The first groynes on the Danish west coast were built at Ferring by what was then Vandbygningsvasenet (VBV) in the period 1875-76.
They consisted of closely fitting rows of poles, the spaces between which were filled with fascines (pine branches). A layer of gravel was laid on top of this, which in turn was secured with heavy blocks of concrete and granite.
The groynes were intended to catch sand and gravel, thus raising and widening the board and thus counteracting coastal receding.
The work of the nail boys
To protect the wooden poles from poleworms, the poles were fitted with copper nails. The distance between the copper nails was 13 mm.
This work was done by local boys who could earn 0.25 kroner for every 1,000 nails driven in. Over time, the boys became so practiced that they could drive up to 1,000 nails an hour into the stakes. The daily wage of a nail boy could be up to 1.25 crowns.